The embodiments herein relate to aircrafts and, more particularly, to an aircraft control system, as well as a method of controlling an aircraft.
Design of rotors and propellers is quite complex. A large number of factors must be taken into account, including flexure of the rotor under heavy loads and the required motions of the rotor blades with respect to the drive mechanism.
Rigid turboprop propeller systems provide collective pitch control of the propeller blades. Pitch angles ranging from a fully feathered minimum drag angle to pitch angles which provide reverse thrust are typically provided to provide propeller speed and power management. Inflow angles not along the axis of rotation due to aircraft maneuvers generate bending moments on the propeller shaft and subsequent twisting of the airframe. The resulting bending moments can be rather large and conventional propeller systems are therefore rigidly structured.
Fully articulated rotors such as those of helicopters provide cyclic and collective pitch of the rotor blades. Articulation of the rotor disc plane vectors the rotor thrust to provide fore, aft and lateral movement of the helicopter with minimal bending moment of the rotor shaft. As compared to rigid turboprop propeller systems, articulated rotor systems of a helicopter are significantly more complex. As such, the control benefits associated with fully articulated rotors are offset by the design and operational complexity.